High-efficiency detoxification of fumonisin B1, B2 and B3 by laccase Lac-W with ABTS

Type B fumonisins (FBs), including fumonisin B₁ (FB₁), fumonisin B₂ (FB₂) and fumonisin B₃ (FB₃), are common mycotoxins in cereal and food products. FBs contamination causes substantial social impacts and economic losses. Effective control of FBs contamination is essential for human and animal health. Laccase Lac-W has the unique property of degrading a variety of mycotoxins in the absence of mediators. Nevertheless, the degradation rates are low. In this study, a laccase mediator system (LMS), Lac-W-2, 2'-azino-bis (3-ethylbenzothiazoline-6-sulfonate) (Lac-W-ABTS), was constructed by screening different mediators, which can improve the degradation rate of FB₁ (34.70 %) within 2 h. By optimizing the reaction conditions (static conditions, pH 7.0, 40 °C, 0.5 U/mL Lac-W, 5 mM ABTS), 1 μg/mL FB₁ was effectively degraded within 24 h (88.25 %), and FB₂ (93.16 %) and FB₃ (78.24 %) were degraded efficiently. The degradation products of FB₁, FB₂ and FB₃ failed to generate cell death of intestinal porcine epithelial cells. Additionally, two detoxification products (hydrolysed FB₁ (HFB₁) and tricarboxylic acid) of FB₁ were identified by high resolution mass spectrometry. Finally, the mechanism by which ABTS acts as a more efficient electron acceptor and thus promotes Lac-W degradation of FB₁ was explained using molecular docking. This work highlights an eco-friendly bio-enzyme method that degrade FB₁, FB₂ and FB₃ simultaneously and efficiently using only one enzyme.